System and a method for processing an image

ABSTRACT

A system and a method for processing an image. The method includes the steps of: receiving a source image having at least one sensitive portions arranged to present intelligible sensitive information; and processing, with a predetermined redacting method, the at least one sensitive portions of the source image to generate an output image including the intelligible sensitive information being transformed into an unintelligible form; wherein the sensitive information in the unintelligible form is adapted to be restored to an intelligible form.

TECHNICAL FIELD

The present invention relates to a system and a method for processing animage, and particularly, although not exclusively, to a system andmethod for redacting sensitive information on an image.

BACKGROUND

Image redaction may be applied to protect sensitive data on images ordocuments. For example, in security surveillance applications, redactionof camera streams may be performed to mask licence plates and/orpeople's faces so as to protect the identity of these subjects. In somecountries, this has to be done to comply with regional privacy laws. Inanother common application, image redaction may be performed to obscuresensitive imagery or information.

SUMMARY OF THE INVENTION

In accordance with a first aspect of the present invention, there isprovided a method for processing an image comprising the steps of:receiving a source image having at least one sensitive portions arrangedto present intelligible sensitive information; processing, with apredetermined redacting method, the at least one sensitive portions ofthe source image to generate an output image including the intelligiblesensitive information being transformed into an unintelligible form;wherein the sensitive information in the unintelligible form is adaptedto be restored to an intelligible form.

In an embodiment of the first aspect, the step of processing the atleast one sensitive portions of the source image includes scrambling theat least one sensitive portions such that the intelligible sensitiveinformation becomes unintelligible.

In an embodiment of the first aspect, the sensitive information in theunintelligible form is adapted to be restored to the intelligible formby reverse-scrambling the at least one sensitive portions in the outputimage.

In an embodiment of the first aspect, each of the at least one sensitiveportions includes a plurality of partitions each include at least oneimage pixel.

In an embodiment of the first aspect, the plurality of partitionscombine to form an array.

In an embodiment of the first aspect, the step of processing the atleast one sensitive portions of the source image further comprising thestep of recording a scrambling arrangement of a plurality of imagepixels associated with each of the at least one sensitive portions.

In an embodiment of the first aspect, the scrambling arrangement isembedded in the output image.

In an embodiment of the first aspect, the scrambling arrangement isencrypted.

In an embodiment of the first aspect, the scrambling arrangement isstored in metadata or header of the output image.

In an embodiment of the first aspect, the method further comprises thestep of processing a plurality of source images each including theintelligible sensitive information presented on the at least onesensitive portions of each of the source image, wherein the plurality ofsource images are arranged to combine as a stream of image frames.

In an embodiment of the first aspect, the step of processing the atleast one sensitive portions of the source image includes scrambling theat least one sensitive portions on different source images withdifferent scrambling arrangements.

In an embodiment of the first aspect, the method further comprises thestep of encrypting a scrambling arrangement associated with each of theimage frames using a plurality of unique encryption keys.

In an embodiment of the first aspect, the method further comprises thestep of identifying the at least one sensitive portions in the sourceimage.

In an embodiment of the first aspect, the intelligible sensitiveinformation includes an identification feature of an object.

In accordance with a second aspect of the present invention, there isprovided a method of restoring an image processed by the method of thefirst aspect, comprising the step of: retrieving a scramblingarrangement of the plurality of image pixels associated with each of theat least one sensitive portions; and reverse-scrambling the at least onesensitive portions in the output image so as to present the sensitiveinformation in the intelligible form.

In an embodiment of the second aspect, the method further comprises thestep of authenticating a user so as to process the steps of retrievingthe scrambling arrangement and/or reverse-scrambling the at least onesensitive portions in the output image upon a valid authentication.

In accordance with a third aspect of the present invention, there isprovided an image processing system comprising: an image processingmodule arranged to process at least one sensitive portions of a sourceimage with a predetermined redacting method, wherein the at least onesensitive portion is arranged to present intelligible sensitiveinformation; and a redacted image generation module arranged to generatean output image including the intelligible sensitive information beingtransformed into an unintelligible form; wherein the sensitiveinformation in the unintelligible form is adapted to be restored to anintelligible form.

In an embodiment of the third aspect, the image processing module isarranged to scramble the at least one sensitive portions such that theintelligible sensitive information becomes unintelligible.

In an embodiment of the third aspect, the sensitive information in theunintelligible form is adapted to be restored to the intelligible formby reverse-scrambling the at least one sensitive portions in the outputimage.

In an embodiment of the third aspect, each of the at least one sensitiveportions includes a plurality of partitions each include at least oneimage pixel.

In an embodiment of the third aspect, the plurality of partitionscombine to form an array.

In an embodiment of the third aspect, the redacted image generationmodule is further arranged to record a scrambling arrangement of aplurality of image pixels associated with each of the at least onesensitive portions.

In an embodiment of the third aspect, the scrambling arrangement isembedded in the output image.

In an embodiment of the third aspect, the scrambling arrangement isencrypted.

In an embodiment of the third aspect, the scrambling arrangement isstored in metadata or header of the output image.

In an embodiment of the third aspect, the image processing module isarranged to process a plurality of source images each including theintelligible sensitive information presented on the at least onesensitive portions of each of the source image, wherein the plurality ofsource images are arranged to combine as a stream of image frames.

In an embodiment of the third aspect, the image processing module isarranged to scramble the at least one sensitive portions on differentsource images with different scrambling arrangements.

In an embodiment of the third aspect, the redacted image generationmodule is further arranged to encrypt a scrambling arrangementassociated with each of the image frames using a plurality of uniqueencryption keys.

In an embodiment of the third aspect, the image processing module isarranged to identify the at least one sensitive portions in the sourceimage.

In an embodiment of the third aspect, the intelligible sensitiveinformation includes an identification feature of an object.

In accordance with a fourth aspect of the present invention, there isprovided an image viewer arranged to restore an image processed by theimage processing system of the third aspect, wherein the image viewercomprise a reverse-redacting module arranged to retrieve a scramblingarrangement of the plurality of image pixels associated with each of theat least one sensitive portions, and to reverse-scramble the at leastone sensitive portions in the output image so as to present thesensitive information in the intelligible form.

In an embodiment of the fourth aspect, the image viewer furthercomprises an authorization module arranged to authenticate a user so asto enable the reverse-redacting module to retrieve the scramblingarrangement and/or to reverse-scramble the at least one sensitiveportions in the output image upon a valid authentication.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments of the present invention will now be described, by way ofexample, with reference to the accompanying drawings in which:

FIG. 1 is a schematic diagram of a computing server for operation as asystem for use in processing an image in accordance with one embodimentof the present invention;

FIG. 2 is an illustration of an image processing system and an imageviewer that may be implemented by the computing server of FIG. 1;

FIGS. 3A to 3C are illustrations showing examples sensitive portionsthat present intelligible sensitive information; and

FIG. 4 is a block diagram showing an operation of the image processingsystem and the image viewer of FIG. 2.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

The inventors have, through their own research, trials and experiments,devised that while there are several techniques available incomputer-vision algorithms to redact images, this redaction isconsidered permanent and not removable. This is because the redactionprocess is done by replacing the original pixels of the image data so asto obscure the image data. This may be performed by replacement withalternative pixels or smudging out portions of the image data.

In one preferred embodiment, the present invention provides a uniquereversible redacting method which allows the redaction to be reversedwhen required. Preferably, the method utilizes jumble blocks of thesensitive portions of an image with a unique code, so that when the codeis reapplied to reverse the jumbled blocks the original image isrestored. This embodiment may conceptually be similar to how a rubik'scube is scrambled and then solved.

With reference to FIG. 1, an embodiment of the present invention isillustrated. This embodiment is arranged to provide an image processingsystem comprising: an image processing module arranged to process atleast one sensitive portions of a source image with a predeterminedredacting method, wherein the at least one sensitive portion is arrangedto present intelligible sensitive information; and a redacted imagegeneration module arranged to generate an output image including theintelligible sensitive information being transformed into anunintelligible form; wherein the sensitive information in theunintelligible form is restorable or adapted to be restored to anintelligible form.

This embodiment is further arranged to provide an image viewercomprising a reverse-redacting module arranged to retrieve a scramblingarrangement of the plurality of image pixels associated with each of theat least one sensitive portions, and to reverse-scramble the at leastone sensitive portions in the output image so as to present thesensitive information in the intelligible form.

Preferably, in one example, the system may be used to identify sensitiveinformation, such as number plates and human faces, presented on thesource image, and to generate an output image with the sensitiveinformation being “masked” using a reversible redaction method, suchthat the sensitive information is not intelligible unless the outputimage is to be further processed to restore the masked portion of theimage using a reversal or a restoring processing method provided in aspecifically implemented or proprietary image viewer.

In this embodiment, the image processing module, the redacted imagegeneration module and/or the reverse-redacting module are implemented byor for operation on a computer having an appropriate user interface. Thecomputer may be implemented by any computing architecture, includingstand-alone PC, client/server architecture, “dumb” terminal/mainframearchitecture, or any other appropriate architecture. The computingdevice may be appropriately programmed to implement the invention.

Referring to FIG. 1, there is shown a schematic diagram of a computer ora computing server 100 which in this embodiment comprises a server 100arranged to operate, at least in part if not entirely, the system foruse in processing images in accordance with one embodiment of theinvention. The server 100 comprises suitable components necessary toreceive, store and execute appropriate computer instructions. Thecomponents may include a processing unit 102, read-only memory (ROM)104, random access memory (RAM) 106, and input/output devices such asdisk drives 108, input devices 110 such as an Ethernet port, a USB port,etc. Display 112 such as a liquid crystal display, a light emittingdisplay or any other suitable display and communications links 114. Theserver 100 includes instructions that may be included in ROM 104, RAM106 or disk drives 108 and may be executed by the processing unit 102.There may be provided a plurality of communication links 114 which mayvariously connect to one or more computing devices such as a server,personal computers, terminals, wireless or handheld computing devices.At least one of a plurality of communications link may be connected toan external computing network through a telephone line or other type ofcommunications link.

The server may include storage devices such as a disk drive 108 whichmay encompass solid state drives, hard disk drives, optical drives ormagnetic tape drives. The server 100 may use a single disk drive ormultiple disk drives. The server 100 may also have a suitable operatingsystem 116 which resides on the disk drive or in the ROM of the server100.

The system has a database 120 residing on a disk or other storage devicewhich is arranged to store at least one record 122. The database 120 isin communication with the server 100 with an interface, which isimplemented by computer software residing on the server 100.

Alternatively, the database 120 may also be implemented as a stand-alonedatabase system in communication with the server 100 via an externalcomputing network, or other types of communication links.

With reference to FIG. 2, there is shown an embodiment of the system 200for use in processing and/or viewing images. In this embodiment, thesystem 200 is used to process a source image 222 and generate an outputimage 224 with at least a portion of the source image being edited orredacted, for example, the human face presented on the source image 222is transformed to an unintelligible form as presented on the outputimage 224.

With reference also FIGS. 3A to 3C, there is shown three examples ofimages with different sensitive portions presenting with intelligiblesensitive information, such as identification features of an object or atarget. For example, one may consider that the entire area showing theface of an individual is the sensitive portion therefore the entire faceas shown in grids 1-24 in FIG. 3A has to be masked or redacted such thatthe identity of the individual is unrecognisable. Alternatively, one mayinstead consider that only the area with facial features on the face ofan individual is the sensitive portion therefore only the center portionof the face as shown in grids 31-50 in FIG. 3B has to be masked orredacted such that the identity of the individual is unrecognisable.

In an alternative example with reference to FIG. 3C, sensitiveinformation may be a combination of alphanumeric characters which mayrepresent an identity of an object. This may include a name or anidentity number recorded on an identity card of an individual, a nameand address of certain premises, or a number plate associated with avehicle. Referring to FIG. 3C, the identity of these objects may becomeunrecognisable by masking a part or all of the alphanumeric charactersbeing presented, such as grids 51-58 in FIG. 3C, in which the textstring “AB 2 EF” will become non-readable after grids 51-58 areredacted.

Now referring back to FIG. 2, the source image 222 may be provided tothe image processing system 202 to redact the face presented on theimage 222. Preferably, the image processing module 204 may process theimage 222 using a predetermined redacting method 210, such as scramblingthe sensitive portion (in this example the entire image 222) totransform the intelligible sensitive information to becomeunintelligible.

In this example, the entire source image 222 is partitioned into ninepartitions (or blocks) 61-69 which combine to form a 3×3 array, and eachof the partitions includes multiple pixels. It should be appreciated bya skilled person in the art that the size and dimension of the array maybe different in other examples, such as 4×6 or 4×5 as shown in FIGS. 3Aand 3B, and the size of each of the partitions may also be different.For example, the size of each partition may include one single pixel,which means that the dimension of the partition array may be identicalto the pixel dimension of the image or the redacted portion of theimage.

After scrambling the image 222 or the sensitive portions of the image222, the redacted image generation module 206 may generate an outputimage which includes the sensitive information in the unintelligible (orscrambled) form. Preferably, when generating the output image, theredacted image generation module 206 may also record a scramblingarrangement of the image pixels associated with sensitive portions suchthat by using the recorded scrambling arrangement, the sensitiveinformation in the unintelligible form may be restored to theintelligible (or original) form by reverse-scrambling the sensitiveportions in the output image 224 generated by the redacted imagegeneration module 206.

For example, referring to FIG. 2, the scrambling arrangement may berecorded as 61-66-68-63-67-65-69-64-62 as shown on the output image 224,such in the reverse-scrambling process 220, the reverse-redacting module214 of the image viewer 212 may rearrange the positions of thesepartitions or blocks of the output image 224 back to the originalarrangement, i.e. sequentially 61-69 from left to right and top tobottom, as shown in the source image 222, such that the originalrepresentation may be restored to reveal the sensitive information.

In this disclosure, the terms “scramble” and “scrambling” mean arrangingthe plurality of pixels or partitions of the target area of an imagebased on an arrangement different from the original one, and the term“reverse-scrambling” means once again arranging these pixels orpartitions, based on a reversal of such an arrangement in the scramblingprocess, so as to revert the previously performed scrambling of thesepixels or partitions. The inventor may also refer such scramblingprocess as a “code-block jumbling” process.

Preferably, the scrambling arrangement may be embedded in the outputimage 224 generated by the redacted image generation module 206, in theform of metadata or header of the output image 224. Alternatively, thescrambling arrangement may be stored as a separate data file with a fileassociation with the output image 224 or multiple output images. Yetalternatively, the scrambling arrangement may be requested and retrievedonly when necessary from a remote repository, to further enhance thesecurity and integrity of the redacted information.

It is also possible that the both image processing module 204 and thereverse-redacting module 214 are pre-programmed to process the imageswith one or more predefined scrambling arrangements such that furtherrecording of the scrambling arrangement become unnecessary in someexample embodiments.

Optionally or additionally, to further enhance the security andintegrity of the redacted information, the scrambling arrangement isencrypted, e.g. by using a crypto engine 208 in the image processingsystem 202 which may encrypt the scrambling arrangement, such that theviewer 212 may perform the reverse-scrambling process after unlockingthe retrieved encrypted scrambling arrangement using the associatedencryption key.

In addition, the image viewer 212 may further comprise an authorizationmodule 216 which authenticates a user so as to enable thereverse-redacting module 214 to retrieve the scrambling arrangementand/or to reverse-scramble the at least one sensitive portions in theoutput image 224 upon a valid authentication. Advantageously, thisensures that redacted sensitive information is not disclosed tounauthorized individuals even though they may have the access to theproprietary image viewer 212 and/or the processed output images 224.

With reference also to FIG. 4, in another example embodiment, the imageprocessing system 202 may also be used to process multiple image 222,wherein images (image₁-image_(N)) are arranged to combine as a stream ofimage frames, and may be playback as a video stream. In this example,each of the source image frames (1-N) includes the same or differentsensitive information and will be scrambled using the redacting methoddescribed earlier in this disclosure.

Preferably, each of the source image frames 222 may be processed usingdifferent scrambling arrangements so as to further minimized the riskthat the sensitive information in all the image frames being hackedeasily. Alternatively, the scrambling arrangements may change at apredetermined time interval, e.g. every 1000 frames, based on differentdesigns of the image processing module 204 and/or the playback module.In addition, the redacted image generation module 206 may encrypt therespective scrambling arrangement associated with each of the imageframes using a plurality of unique encryption keys to further protectthe sensitive information, although it is also possible that the sameencryption key may be used for encrypting the same or differentscrambling arrangements for all image frames, or the encryption key usedmay change at a predetermined time interval in other designs.

In one preferable embodiment, the reversible redacting method enablesredaction in two main objects in surveillance camera video stream,namely human face and vehicle number plate. Optionally, the imageprocessing module 204 may be implemented to identify the objects inthese sensitive portions in the source image, for example, by using anAI-based object recognition module to identify the target area of theimage to be processed by the reversible redacting method. Alternatively,the object of interest, such as human faces or vehicle number plates,may be detected using other computer vision techniques.

Once this is done, the image coordinates of these objects may beenclosed in a polygon, such as but not limited to, a rectangle or asquare. This polygon is then divided into blocks which are interchangedto a unique code that is unique code per customer or user. This codethen becomes the key by which the image is redacted.

For example, image portions showing a face or a number plate may becropped from the source image of a video stream. The object in the imagemay be divided into multiple partitions/blocks, such as 16 or 8 blocks.The number of blocks each object may be divided decides the complexityof the redaction process and may be user configurable. Once the objectis divided into blocks, the blocks may be rearranged in a certain uniqueorder per image. The jumbled blocks are then altered the stitched backon the original image.

The order in which the objects are rearranged for the image may then bestored in the metadata of that image which is then embedded as the framedata and encoded as a video stream. The encoded video stream may beONVIF compliant stream and can be used similar to any camera streamsupplied by most ONVIF conformant video management systems or NVRs insome example applications.

Although the encoded video stream is ONVIF conformant and can be used byany VMS or NVR system, to reverse the redaction the video must be passedback to a proprietary video player. Otherwise, referring to FIG. 4, ageneric image/video viewer may only be able to produce a representationof the process output images 224 with a “redacted view” 404 with thesensitive information, such as the human faces and/or number platesremains redacted.

When the encoded redacted images/video 224 is passed through theproprietary image viewer 212 or video player, the player decodes thevideo into individual frames, and then reads the frame's metadata thatcontains the unique code to retrieve the recorded scramblingarrangement. Using the unique code, the order in which the blocks arearranged is determined and the blocks are reversed in order. Thereversing process restores the original view 402 of the image, which isconverted to an encoded video frame. The video may then be rendered inthe player for the user to see without redaction. The original view 402of the image or the video stream should be the same or at least notsubstantially different from the view produced by a generic image viewerthat renders the source image(s) 222 without being processed by theredaction method.

To further enhance the data security, similar to the redaction andreversing process, the data security process handled by in both theabove processes may also be unique. The encoding process after redactionand also the data retrieving process by the video player beforereversing the data may be digitally protected. The secure data handlingduring the entire process may involve one or more of the followingexample operations:

I. The number of blocks dividing the object in the image may be variableand configurable. This allows the jumbling of blocks more complexaccording to user's consideration of data sensitivity.

II. The order of jumbling the blocks may be encrypted using AES 256 andthe encrypted key may be stored in the header of same frame. This meansthe encrypted data can only be decrypted by a known system or imageviewer, such as the proprietary player.

III. The encryption key may be varied every frame, because the order inwhich the blocks are jumbled may be changed every frame. The encryptedkey may also be unique to every frame. This means, even if one frame ishacked the user may not be able to decrypt another frame easily.

IV. Although the redacted video may be consumed by open networkstandards, the reversing process is controlled only by proprietaryplayer. This limits the software availability only to authorised users.

V. The video player may be provided with features of authorised usermanagement, tokenised functions after authentication making the streammore secured.

These embodiments may be advantageous in that the reversible redactionmethod may be applied to any image or video stream and not restricted tosurveillance video streams, and provides an effective way to enableconversions of sensitive information between an intelligible form and anunintelligible form without sacrificing the details of the redactedportions of the image.

Advantageously, the method may be used in different applications, suchas but not limited to, real-time redaction of surveillance camera videostreams, recorded video archives, general video evidences for regulatoryfirms, video evidences collected for law-enforcement agencies, socialmedia video content and main stream media platforms.

It will also be appreciated that where the methods and systems of thepresent invention are either wholly implemented by computing system orpartly implemented by computing systems thus any appropriate computingsystem architecture may be utilised. This will include standalonecomputers, network computers and dedicated hardware devices. Where theterms “computing system” and “computing device” are used, these termsare intended to cover any appropriate arrangement of computer hardwarecapable of implementing the function described.

It will be appreciated by persons skilled in the art that the term“database” may include any form of organized or unorganized data storagedevices implemented in either software, hardware or a combination ofboth which are able to implement the function described.

It will be appreciated by persons skilled in the art that numerousvariations and/or modifications may be made to the invention as shown inthe specific embodiments without departing from the spirit or scope ofthe invention as broadly described. The present embodiments are,therefore, to be considered in all respects as illustrative and notrestrictive.

Any reference to prior art contained herein is not to be taken as anadmission that the information is common general knowledge, unlessotherwise indicated.

1. A method for processing an image comprising the steps of: receiving asource image having at least one sensitive portions arranged to presentintelligible sensitive information; and processing, with a predeterminedredacting method, the at least one sensitive portions of the sourceimage to generate an output image including the intelligible sensitiveinformation being transformed into an unintelligible form; wherein thesensitive information in the unintelligible form is adapted to berestored to an intelligible form.
 2. The method of claim 1, wherein thestep of processing the at least one sensitive portions of the sourceimage includes scrambling the at least one sensitive portions such thatthe intelligible sensitive information becomes unintelligible.
 3. Themethod of claim 2, wherein the sensitive information in theunintelligible form is adapted to be restored to the intelligible formby reverse-scrambling the at least one sensitive portions in the outputimage.
 4. The method of claim 2, wherein the step of processing the atleast one sensitive portions of the source image further comprising thestep of recording a scrambling arrangement of a plurality of imagepixels associated with each of the at least one sensitive portions,wherein each of the at least one sensitive portions includes an array ofpartitions each include at least one image pixel.
 5. The method of claim4, wherein the scrambling arrangement is encrypted.
 6. The method ofclaim 4, wherein the scrambling arrangement is stored in metadata orheader of the output image.
 7. The method of claim 2, further comprisingthe step of processing a plurality of source images each including theintelligible sensitive information presented on the at least onesensitive portions of each of the source image, wherein the plurality ofsource images are arranged to combine as a stream of image frames. 8.The method of claim 7, wherein the step of processing the at least onesensitive portions of the source image includes scrambling the at leastone sensitive portions on different source images with differentscrambling arrangements.
 9. The method of claim 7, further comprisingthe step of encrypting a scrambling arrangement associated with each ofthe image frames using a plurality of unique encryption keys.
 10. Themethod of claim 1, further comprising the step of identifying the atleast one sensitive portions in the source image.
 11. The method ofclaim 1, wherein the intelligible sensitive information includes anidentification feature of an object.
 12. A method of restoring an imageprocessed by the method of claim 3, comprising the step of: retrieving ascrambling arrangement of the plurality of image pixels associated witheach of the at least one sensitive portions; and reverse-scrambling theat least one sensitive portions in the output image so as to present thesensitive information in the intelligible form.
 13. The method of claim12, further comprising the step of authenticating a user so as toprocess the steps of retrieving the scrambling arrangement and/orreverse-scrambling the at least one sensitive portions in the outputimage upon a valid authentication.
 14. An image processing systemcomprising: an image processing module arranged to process at least onesensitive portions of a source image with a predetermined redactingmethod, wherein the at least one sensitive portion is arranged topresent intelligible sensitive information; and a redacted imagegeneration module arranged to generate an output image including theintelligible sensitive information being transformed into anunintelligible form; wherein the sensitive information in theunintelligible form is adapted to be restored to an intelligible form.15. The image processing system of claim 14, wherein the imageprocessing module is arranged to scramble the at least one sensitiveportions such that the intelligible sensitive information becomesunintelligible.
 16. The image processing system of claim 15, wherein thesensitive information in the unintelligible form is adapted to berestored to the intelligible form by reverse-scrambling the at least onesensitive portions in the output image.
 17. The image processing systemof claim 15, wherein the redacted image generation module is furtherarranged to record a scrambling arrangement of an array plurality ofimage pixels associated with each of the at least one sensitiveportions, wherein each of the at least one sensitive portions includesan array of partitions each include at least one image pixel.
 18. Theimage processing system of claim 17, wherein the scrambling arrangementis encrypted.
 19. The image processing system of claim 17, wherein thescrambling arrangement is stored in metadata or header of the outputimage.
 20. The image processing system of claim 14, wherein the imageprocessing module is arranged to process a plurality of source imageseach including the intelligible sensitive information presented on theat least one sensitive portions of each of the source image, wherein theplurality of source images are arranged to combine as a stream of imageframes.
 21. The image processing system of claim 20, wherein the imageprocessing module is arranged to scramble the at least one sensitiveportions on different source images with different scramblingarrangements.
 22. The image processing system of claim 20, wherein theredacted image generation module is further arranged to encrypt ascrambling arrangement associated with each of the image frames using aplurality of unique encryption keys.
 23. The image processing system ofclaim 16, further comprising an image viewer including areverse-redacting module arranged to retrieve a scrambling arrangementof the plurality of image pixels associated with each of the at leastone sensitive portions, and to reverse-scramble the at least onesensitive portions in the output image so as to present the sensitiveinformation in the intelligible form.
 24. The image processing system ofclaim 23, wherein the image viewer further comprising an authorizationmodule arranged to authenticate a user so as to enable thereverse-redacting module to retrieve the scrambling arrangement and/orto reverse-scramble the at least one sensitive portions in the outputimage upon a valid authentication.